Conventionally, internal communications of an information processing apparatus and external communications between an information processing apparatus and another information processing apparatus are often achieved as parallel communication using a transmission path with 2α (αis a positive integer or 0) transmission lines to transmit data having a data width of 2α bits in a parallel manner, where 2α represents the α-power of 2.
In such parallel communications, when a transmission error occurs in a transmission line, to ensure communication reliability, at least communication using that transmission line has to be suspended.
To achieve this, in a conventional technology, the transmission path in use is equally divided into two segments. The use of a segment including a transmission line where a transmission error occurred is stopped. The data width of the transmission path is divided into ½, and data transmission continues by using the other segment whose use is not stopped. With this, even if a transmission error occurs in a transmission line, the transmission path can be continuously used, while maintaining communication reliability.
Such a conventional technology is disclosed in, for example, Japanese Laid-open Patent Publication No. 05-250317.
However, in the conventional technology, every time a transmission error occurs in a transmission line of the transmission path in use, the data width of the transmission path including a segment where no error occurs is excessively degenerated to ½.
Moreover, every time a transmission error occurs in a transmission line, the transmission speed of the transmission path is further decreased to ½. A decrease in transmission speed leads to a decrease in throughput of the information processing apparatus, thereby inviting an unwanted stay of transmission data and a delay in transmission of data to be transmitted with the highest priority.